Wiring domestic telephone sockets

[Loki]

I haven't touched the master socket only unscrewed it to check the connections. Should it be solid blue to the A connection?

doesnt matter which way round for A & B

if you take off the master socket front you will see the master socket test socket.
test your phone in that. do you get a dial tone? if not then the fault is either at the A,B connections or bt side

 

[littlespark]

You shouldn't need to unscrew the master. Only remove the small panel at the bottom. That's where you connect any extensions to.

Your incomer from BT or whoever only has 1 pair of wires.